The aim of this study was to examine the effect of atorvastatin treatment on levels of leptin, adiponectin and insulin resistance, and their correlation with clinical parameters, in patients with type II diabetes. Patients with diabetes (n=394) were divided into two groups, comprising 161 patients who received 20 mg/day atorvastatin (statin group), and 233 patients who did not receive statins (statin-free group). The results showed that atorvastatin treatment of patients with diabetes was not associated with changes in leptin, adiponectin, the leptin/adiponectin (L/A) ratio or homeostasis model assessment-insulin resistance (HOMA-IR). However, low-density lipoprotein cholesterol (LDL-C), triglycerides (TG) and total cholesterol (Tchol) were positively correlated with leptin and L/A ratio in the statin group only (P<0.05). By contrast, high-density lipoprotein cholesterol (HDL-C) showed a significant positive correlation with adiponectin in the statin and statin-free groups (P<0.05). Additionally, a positive correlation was found between HOMA-IR and glycated hemoglobin (HbA1c), and TG, in both groups, whereas Tchol was positively correlated with HOMA-IR in the statin group only (P<0.05). When multivariate analysis was performed with HOMA-IR as the dependent variable, and with adjustment for age, body mass index (BMI) and waist circumference, HbA1c was found to be a significant predictor of HOMA-IR or insulin resistance. In conclusion, atorvastatin treatment may have several effects on the interaction between leptin and adiponectin, and on clinical parameters in patients with type II diabetes.